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engine combo - 1127 block, crank, piston,head in '88 750 case.

25K views 46 replies 9 participants last post by  TESTO 
#1 ·
guys, i have searched till i gave up!

as per above :
am trying to fit a 1127 block,crank,pistons,head into my '88 750 engine case. :fact

havent get my hands dirty yet tho, but finding out what fit & what doesn't would really help me in advance! :hammer

also read somewhere about some more engine combos, but i've confused myself with the search.

so in short, i got a long-time-project-nearly 90% dis-assembled 1127 and head-less 750.

TIA
 
#2 ·
naj i bought one, crank ground down 1127 ,1127 rods 750 case bored, 1127 barrels
and head .crank journals were cooked ? as well as 1 rod big end that is beside my computer
i'd be using the 1127 bottom with dot 750 head iff your cases are ok
 
#3 ·
thanks OG!

was trying to retain the 6 speed, whenever possible. did the valve job on the 1127's head recently, coudn't be bothered doin' it on the ******** (yea i have one)

did multiple search, and did not found anything that fits my question.

so only the crank needs to be modified to fit in the 750's case?

figured that if i got the case cleared to accept the 1127's crank, everything else frm the 1127 (rods,block,head) wud then be bolted onto the 750's case.

also have a set of 1216 JE piston kit, just in case this does not work out well :D
 
#4 · (Edited)
some more digging in here. here's what i found

" OK, here's the full scoop on oil-cooled cases:

There are two basic groups of oil-cooled cases, and the primary reason for the difference between them is the size of the main bearings. All of the 600's and all of the long-stroke GSXR 750's use the small main bearing setup. All of these cases are mostly interchangeable with each other.


The other group of cases uses the large main bearings, and this would include all of the 1100's, Bandit 1200's, and all of the short-stroke 750's. Short stroke 750's are any of them that had a 73mm piston from the factory, including 88-89 GSXRs and all of the Katana 750's. All of the cases from this group of engines are mostly interchangeable.


But, as I said, mostly interchangeable. During the lifespan of the oil-cooled, Suzuki made 2 upgrades that affect the case interchangeablility. The first upgrade was to the starter motor. The 1052 motors use exactly the same cases and starter dimensions as all of the short-stroke 750's, with the only difference being the color of the paint on them. The GSXR's had a dark grey, while the Katanas had a semi-gloss black. Other than that, all 1052s and short-stroke 750 cases are identical.


When the 1127 motor came out in 89 (88 on the 1100 Katana), they upgraded the starter motor. The newer starter has a larger output bearing. As a result, the cases have a larger bore in them for the starter, and the gasket surface of the starter cover has a slight hump around the starter area as compared to an earlier motor. You can change cases between the small starter and the large starter, but you must also change over to the correct starter and engine cover appropriate for the new cases.


The next upgrade was to replace the transmission output shaft bearing. The early motors used a single-row bearing, which was prone to breaking. So starting in 1991 Suzuki started to use a double-row output bearing in the GSXR 1100's. I believe that this is also the same setup used in the Bandit 1200's as well. But they never upgraded the Katana 1100s to this setup and, to my knowledge, they never upgraded any of the 750 Katana engines either.


This modification affects the cases because the location of the retainer groove is different between the 2 different bearings, and is therefore different between the cases as well. So if you are swapping cases that have different groove locations, you must have a transmission with the correct output bearing and output shaft to match the cases.


Now more specifically to your case, if you truly have a 1989 GSXR 1100 engine (the V710 number is not enough information to positively determine this), then the only 100% direct replacement cases would be 89-90 GSXR 1100 and 88-93 Katana 1100 cases. Others could be made to work, but they would all require some modification or swapping of some parts.

"

and

" ok I finally got some time to play with the motor. Grinded all the cases smooth on the inside for better oil return as the 88 cases have some casting ridges that collect alot of slug. got all the bearings including the thrush bearing (really important). It's perfect on the thrush .003 in with required .002 to .005. that was my biggest worry because the crank is beefier the the 750.
I know there is a guy from australia on this site that has done this for racing before and if you out there please hit me up.
my clutch is the 88 1052 clutch and matches up with the oil pump and transmission and is all ready to drop in.
The spot for #3 rod that you have to grind down is not much but looks like it is on an oil galley so be very careful as you will finish the build right there if you go thru. It only flattening it out a tiny bit otherwis the cases are the same
"

'looks like it is on an oil galley' ?

any pic of that area in particular?
 
#5 ·
well i figured you guys love pics. here's some progress.:hammer

turns out i may re-use the lower half of the 1127's case, which eliminate the need for crankshaft gap issues. no grinding needed!

but the hydraulic clutch setup will be ditched, since i can't use it!

i wonder whether will the 750's stock clutch hold up well against the 1216?
 

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#6 ·
looking good NAJ, thanks for putting up the info
 
#7 ·
that sorta comment comin' from a senior? i'm flattered, OG! :punk
will be using a 36mm carby, the block is being punched to accomodate 81mm JE's, and cable clutch (i still can't remember why i can't use hydraulic! :hammer)

am not gonna go for max hp, i just want a weekend bike i can enjoy.

we will see:

-whether a 6-speeder will withstand a 1216 (or not)
-a 750 stock clutch vs 1216's torque

anything else you guys want me to test out while i'm at it?

no write-up, but will take some pics as i go along.
 
#8 ·
just wanted to encourage you doing it yourself , i'd be adding more clutch pressure by the way of a lockup that clamps more pressure on the plates as rpm increases
 
#9 ·
That is f-n cool! Keep up the good work and post as you go. I never considered that you could use the big-block bottom case with it. It'll be interesting to see what the weight difference will be compared to the OEM 748 engine.
 
#10 ·
:fact

picture: 1127 block now sits comfortably on 748's upper part of the crankcase. case needs to be slightly machined for the block's clearence, else the block just won't sit flush. i sent them to a machine shop nearby, and excuse the crappy pic, i am no photographer!

now on to punchin' the hole a tad bigger for 81mm pistons. :chucks
 

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#11 ·
righto.

the case shows where some grinding is required in order to fit a 1127 block on to a 748's case.

the blocks will fit 81mm pistons now.
look at how slim the cylinder walls are! scary stuff! :dunno
 

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#12 ·
the blocks will fit 81mm pistons now.
look at how slim the cylinder walls are! scary stuff! :dunno
just remember the sleeves are supported at each fin from swelling under pressure not like a car engine , keep the progress coming
 
#14 ·
snapped some better-lookin pics of em before assembly :wait
 

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#16 ·
i have no idea, sent it to a machine shop that did it for me.
will the ruff grind be an issue later on? (no, really.. would it? :dunno)
 
#18 ·
Lots of have been done by hand with a die grinder and are far from perfect..
It will be fine!! You now have the clearance needed for the bigger sleeves to drop down into the case, the block is supported at the top of the case.

Great build! :cheers
thanks! point noted! :cheers
 
#19 ·
lack of update! work is f*n murder!

but pistons are already assembled, will upload some pics soon!
 
#20 ·
some progress pics!
everything on the engine block is assembled, minus clutch assembly tho.
 

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#21 ·
just found out i've a cracked oil sump!

had it TIG-welded yesterday.

what else can go wrong eh?:hammer
 

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#22 ·
can't find my 750j starter motor anywhere in the parts bin! so i had my 1100m starter motor slightly modified & shaved to fit the puny hole in the 750's case.

and that is a slightly modified ( shortened, narrowed ) SRAD tail. maybe using that, maybe not :dunno
 

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#23 ·
In post #5 of this thread,
you mention possibly using an 1127 bottom case half with a slingshot 750 top case half.

Did you end up doing this?
You know cases are line honed after being factory assembled,
and if you mismatch a set you would have to re-line hone them together, right?
(If the cases were mismatched enough, this might not even be possible)

You didn't mention it again, so you are probably using the matched 750 set now,
but I was just wondering.

Good build by the way :cheers

There are other threads about using the 6speed behind an 1100.
Most that have tried it do not recommend it.

Either way, good luck!
 
#24 ·
In post #5 of this thread,
you mention possibly using an 1127 bottom case half with a slingshot 750 top case half.

Did you end up doing this?
You know cases are line honed after being factory assembled,
and if you mismatch a set you would have to re-line hone them together, right?
(If the cases were mismatched enough, this might not even be possible)

You didn't mention it again, so you are probably using the matched 750 set now,but I was just wondering
no i didn't know that line hone thingy. everything just fits so well, i guess it'll work? :dunno but NOW i'm worried! :suicide

so what should i look out for? i haven't sort out the electrics yet, but using a wrench, the crankshaft convincingly rotates well enough. no grinding sound? :scratch


Good build by the way :cheers

There are other threads about using the 6speed behind an 1100.
Most that have tried it do not recommend it.
just tryin' out something a bit different. :cheers
i was comparing between them 5 & 6 speed boxes prior to the build and i assume they wouldn't break THAT easy. i did a search on that part too, and regardless of the previous posts, i decided to do a write up on my own to prove something.

i'm not doing any form of racing, maybe a trackday or two in the future, but i was building the bike for fun.i rarely have the time to ride, tho. :sleep

i still have the 5 speed box as spare if anything goes wrong.
 
#25 ·
I like! I too have an all the wrong parts motor though mine is a bastard gsx600f and gsx-r750 blend. In my i used a 90' clutch, 6 springs, only because i didn't have a clutch for the 4 spring basket and i got it for free .99. You might be able to use a GS clutch basket I'll have to look through my misc stuff and see if the 1100 basket i have will fit on one of the many 88- trans shafts i have. it's kinda funny how you can cross parts over many years of GS-GSX-GSXR some directly some you kinda have to force err make work.

I will say that i do know a guy that threw 2nd out the back of his short stroke but he also like to yank wheelies on the highway.

here is my mixed bag
 
#27 ·
googled and found this

"LINE HONING is a term to describe the following: Shaving the main caps of the block so that you effectively allow room to "line Bore" another hole in the main journals to re-align them and make them round and straight. So typically, they might shave .002 off the main caps, and then torque down the caps to the block, and then bore the hole of the mains straight and to the spec size they want.

The reasons that are given to such a practice is obvious. The current main alignment is out of spec, or one or more of the holes is out of round. The attempt to fix this is done by a boring bar. These are expensive apparatus's and requires extensive, professional operators to get it right."

"professional operators" :p

i have none of that sort of equipment over here.
i've to risk it this time, since all holes & studs perfectly lined up.
 
#28 ·
the letters on the back of the cases state the I.D. journal size for example i have 2 sets of 88 759 cases that are AAA AAB and another is ABB AAA. the crank will also have letter letting you know how big the O.D. of the crank, only one i have out is a katana 600, it's CBB BBB (the mark is next to rod #1). there is the spec on page 75-80 (3-42 thru 3-47) of the 88-91 750 manual that then lets you know what bearings you would need but that is for the 750 you should also look at page 73-76 (3-40 thru 3-43) of the 88-92 1100 manual to see if and how the tolerances might fit together.

to loose and you can spin a bearing which would ruin the cases and to tight can crack the cases or damage the crank journal.

there is also the thrust bearing that hasn't been mentioned that would also need to be checked to make sure that it's with in tolerance

plasti-gauge is your friend, you may want to split the cases and make sure that your with in the tolerances it kinda sucks but it's better to waste a bit of time taking it apart now and be sure than to have to pull it out and find that stuff is screwed.

I'm no Uber-Tech, more of a shade tree parts replacer though my tech friend calls me for oil cooled info, i have read most of the oil cooled manuals front to back many times and went through all this with my frankenmotor. i have had most of them in hard copy for about 18 years. i thought i had read some where that there is a issue with the larger sleeves and clearance in the cases but i'm not 100% on that one. i do remember some guy talking about doing something like this at the katana forum. though i think he was trying to just put a 750 trans in 1100 cases
 
#29 ·
wow daiyum all that point to note for. :banghead

here i am just tryin to put pieces of my motor back together. last night i thought well ok everything lined up perfectly (i did some measurement n stuff like that) so i'ma go ahead and gonna try to crank her up next week, and now i think i've to split her up again and do some more checking! :crying
 
#30 ·
updates updates!

everything bolted up, test crank with starter = no crank (!)
the starter motor turns fine when unbolted.

possible culprits:

-starter clutch gone bad?

-that 11.0:1 compression too much for the starter?

-new shims, valve clearance too tight?

gotta split the motor up again, either way. duhh!
 
#31 ·
did you see if your motor will turn by hand? as i had a similar problem with a 250 i did it, turned out to be the starter lazy /weak. it would turn out like it should but not turn when i put it back in. did you check to make sure the starter is not binding when in place as you said you had to modified the starter motor
 
#32 ·
turn by hand you mean using a wrench, right?

scuse me but slept late last nite. everything's kinda groggy :hammer

and how do you know when a starter gone bad/weak?
 
#36 · (Edited)
just for the record: :fact

my stock 1127 bores are +3mm enlarged
piston to wall clearence is is about 0.500" up measured from the bottom of skirt.

the spec sheet says "Min. Gap Per Inch of Bore" for
"High-Perf. Street-Strip" use. sheet also says "Clearances listed below are minimum. Some applications such as supercharged, turbo, nitrous and endurance applications may require additional clearance (.001-. 003")"

so 81mm piston = 3.188"

spec sheet says for bore range from 2.500" to 3.625" min piston to wall clearance required
is between 0.0030 to 0.0036.

these pistons are forged with lower silicon content, so they are less brittle, but they expand more.
it says "Your pistons are manufactured from 2618 non-silicon aluminum alloy".

the piston to wall gap is looking kinda big now tho! imo they're gonna rattle like a diesel lol!
even the sheet says "Some applications such as supercharged, turbo, nitrous and endurance applications may require
additional clearance (.001-. 003")."
how about that!

some pointers for end gap:
"End Gap
End gap is the clearance between the two ends of a piston ring as it is installed in a cylinder (fig. 7). Most high performance and racing engine builders purchase piston rings slightly oversized in order to file fit them to very precise end gaps. Testing has shown measurable increases in horsepower and decreases in blow-by as a result of properly fitting the ring end gap to the operating conditions. Factors such as supercharging, turbocharging, nitrous oxide, endurance racing and different fuels determine proper ring end gap. Proper ring end gap can be more than double from one engine to the next depending upon the above factors.


At operating temperature, the top ring end gap should be as small as possible. Precise machining of the cylinder bores is critical, and is the reason why rings should be fitted to the cylinder in which they are to be installed. A diameter variance from one cylinder to the next changes the end gap of the rings in that cylinder by a factor of pi (3.1416).

For example, a cylinder .001” larger in diameter will increase the ring end gap by .001 x 3.1416 = .003”,
rounding off, which could increase cylinder leakage in that cylinder and decrease performance"


since i'm building it for street use,

bore X 0.0045" for 1st ring
bore X 0.0050" for 2nd ring
0.0015 oil ring

means:

3.188" X 0.0045" = min of 0.014346" gap 1st ring
3.188" X 0.0050" = min 0.01594" gap 2nd ring
min gap of 0.0015 for the oil ring

someone verify my calculations there fer me? it's muh 1st build! i'm scairt, paww!

and haven't tried the test start without plugs removed yet (if it doesn't turn so my starter is gone yes?)

either way will know soon enuff.
 
#37 ·
and haven't tried the test start without plugs removed yet (if it doesn't turn so my starter is gone yes?)
If it turns easily by hand with the plugs out but not with the starter then yes, I'd try a new or different starter.

By the way, thanks for the detailed writeup. I haven't built an engine since I rebuilt my Camaro engine (327 V8) but I'm re-assembling a 955 for my project bike so this will be very helpful as I check everything during assembly.
 
#39 ·
out of topic, but this looks interesting enuff.

stumbled upon this on a french (?) site while googling for ideas.

























great stuff people!:woot
 
#40 ·
This is what I’ve been up to (and decided)
Ditching my mikunis for EFI & microsquirt
Will do simple things only(batch fire injectors, fuel only control, spark from stock cdi )

Fuel system :
TB is from gsxr 1000k5, complete with fuel rail, 240cc injectors, TPS.
The secondary butterfly (was an absolute bitch to remove! Needs to be heated properly before the tiny screws can be taken out) is not needed as it’s controlled via a servo & stock ECU.
Removed the secondaries & servo, cleaned etc etc. (that was the easy part!)
That another shiny fuel rail is from an audi TT, complete with 3 bar fuel regulator & 380cc injectors. Might be using that

Carb#1-#2 spacing is off about 1mm with TB#1-#2 (see pic) , so I’d figure it’ll fit the stock intake manifold with minor persuasion.
Needs re-spacing between 3rd &4th tho. Fuel rail also needs altering. That will be detailed later!

More worried about the wiring rather than the fabrication of the fuel system, mounting the fuel pump, etc etc.

I’ll worry about that later!
 

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